1. Field of the Invention
This invention relates to exercise machines, and more particularly to an exercise machine especially useful for athletes to strengthen and rehabilitate shoulder injuries and the muscles of the rotator cuff.
2. Discussion of Related Art
The rotator cuff or musculotendinous cuff consists of the fibers of the supraspinatus, infra-spinatus, teres minor, and subscapularis muscles, which blend with and reinforce the capsule of the shoulder joint. The rotator cuff is of importance because degeneration and subsequent tearing of its tendon of insertion is rather common pathology which results in restriction of shoulder movement, especially in abduction. It is important to keep these muscles strong and in good range of movement.
Many exercise machines are known. However, none of these known machines is specifically adapted to isolate and exercise the rotator cuff.
Some exercise machines can be used to exercise arm muscles in general. For example, U.S. Pat. No. 4,257,590 to Sullivan et al shows a portable home gymnasium which includes handle grips attached through cables to a weight. Movement of the handle grips moves the weight against gravity to exercise the arm muscles.
Other exercise devices are known which operate by movement of a weight or weights against the force of gravity. For example, U.S. Pat. No. 4,333,644 to Lambert, Jr., et al and U.S. Pat. No. 4,125,258 show exercise machines which include weights carried on a frame and guided by guide rods. The weights are attached through a cable to a grip or the like for pulling the weights along the guide rods.
Some exercise machines are adapted to isolate and exercise only a limited number of muscles of the body. For example, U.S. Pat. No. 3,921,975 to Pridgen shows a leg muscle exercise apparatus while U.S. Pat. No. 2,929,375 to Spinks shows a hand supinator.
U.S. Pat. No. 284,024 to Kelly shows a gymnastic chair comprising a rocking chair and a pair of adjustable arm supports attached to the seat of the rocking chair. Gymnastic exercises can be performed in the chair with the arms of the occupant supported at the sides of the chair.